isn't it rather an immature male common darter, based on the anal appendages, see chrisbrooks site, http://www.dragonfly-images.co.uk/#/common-darter/4531918204 ;the text points out the "anal appendages will need close examination" to distinguish a female from an immature male. Your photo gives a clear view & looks identical to appendages of the orange male. The chribrooks site, in further images, shows both female & immature males (not good enough to show endparts) , but a good view of the female is at http://www.ispot.org.uk/node/351764